Recent advances in digital signal processing techniques and, in particular, advancements in digital compression techniques, have lead to a plethora of proposals for providing new digital services to the customer's home via existing telephone and coaxial cable networks. For example, it has been proposed to provide hundreds of cable television channels to subscribers by compressing digital video, transmitting the compressed digital video over conventional coaxial television cables, and then decompressing the video at the subscriber's set-top terminal. Another proposed application of this technology is a movie-on-demand video system in which a subscriber communicates directly with a video service provider via telephone lines to request a particular video program from a video library, and the requested video program is routed to the subscriber's home via telephone lines or via the coaxial television cables for immediate viewing.
Within these systems, control information to facilitate operation of the set-top terminal within the subscriber's home is typically sent as control packets within the video data stream. These control packets contain certain header information which enables the set-top terminal to differentiate between video data and control data. Consequently, the use of packets for sending control data through the video data channel inherently reduces the amount of bandwidth that is available for transmitting video information to the subscriber.
Additionally, the control information that is sent from the set-top terminal to the service provider is typically sent via the telephone system. As such, the subscriber is required to have a dedicated telephone line to provide interactive functionality for the video system. Furthermore, the low data rate of the telephone system does not permit extensive communications between the set-top terminal and the service provider. As such, these systems generally provide rudimentary control commands such as selection of a service or particular information via a menu on the subscriber's television screen.
Therefore, there is a need in the art for a method and apparatus that provides an independent control channel for carrying control information from a set-top terminal to a service provider of an information distribution system without impacting the information bandwidth carrying information to the set-top terminal from the service provider.